I'm an Indian Today is a Little Golden Book, published in 1961. It is out of print. Author was Kathryn Hitte, illustrator was William Dugan.
One page after another, it is a perfect example of stereotyping and how a white child played/plays Indian.
Considering the publication year, it was something someone in my age group (50-60) would have been able to buy.
Maybe this guy, in this costume, read that book when he was a kid... This photo is from a costume site.
